| 摘要 |
A mold plug for use in a mold, the mold being used in a rotary concrete casting process to make a cast article, the mold plug comprising: a rigid internal core having an internal engagement means to secure the plug in the mold during casting and to facilitate removal of the plug from the cast article after casting is complete; and a pliable external cover on the internal core , the external cover having a surface adapted to not bond with concrete, and having a predetermined size and shape, wherein, when the mold plug is removed from the cast article after the casting is complete, a hole of a predetermined size and shape is left in the cast article.
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